Introduction to Image

(Differencesbetween Scion Image
1.61 and NIH Image 1.61 are shown in magenta. Notes
specific to ImageJ are shown in green. For an introduction to ImageJ,
please see the ImageJ
web site. In a way, ImageJ is simpler - the only window that opens upon
starting the program is this:

Upon starting the application, no image will be shown.
Images are shown when you open them with the File menu, drag an
image onto NIH Image, or double click on an image that is 'registered'
as an NIH (Scion) Image document.

The Info window initially appears blank. Clicking the middle of the line
in the Map window and moving it a bit (arrow a) shows the
upper and lower limits (a) (Scion Image - limits
not shown). Clicking on the Info window title bar (c) will
show the Count, area, mean (zero becaure there is no image yet)(Scion
Image - these three as yet meaningless parameters are not shown).
Moving the mouse in the LUT (arrow b) will show the intensity level
and the colors assigned to it.

Set units to pixels with Analyze -> Set Scale... menu. Don't leave units as 'arbitrary.'

Colors in Image

In b above, why are the RGB colors 206 for an index of 109? Two
reasons: in Image (for historical reasons - I believe Image was initially
developed to analyze gel chromatographs, where the background is light and
stains are dark), low pixel values are white and high pixel values are black.
The second reason is that the line in the Map bar was moved.

Clicking on the reset button (arrow) in the Map window resets the
line (and the gray level bar in the LUT window).

Then moving the cursor (it looks like the eye-dropper when over the LUT
window) to the arrow (right) shws this in the Info window:

For gray level images (such as this gray level ramp), the red, blue and
green components are the same.

The Index and the intensity level sum to 255. Note - Index 0 has a level
of 255, and index 255 has a level of zero.

Windows

Images are shown in windows that can be moved about indepently about on the
screen. The tool windows can also be moved - by dragging the title bar. There
is only one IMAGE window that is in the front or active at any one time. The
title bar of the active image winow will be noticably different from
the others.

Tools

Tools affect how the cursor appears, and what clicking and dragging will do.